/*
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
*/

const HASH512_H0: u64 = 0x6a09e667f3bcc908;
const HASH512_H1: u64 = 0xbb67ae8584caa73b;
const HASH512_H2: u64 = 0x3c6ef372fe94f82b;
const HASH512_H3: u64 = 0xa54ff53a5f1d36f1;
const HASH512_H4: u64 = 0x510e527fade682d1;
const HASH512_H5: u64 = 0x9b05688c2b3e6c1f;
const HASH512_H6: u64 = 0x1f83d9abfb41bd6b;
const HASH512_H7: u64 = 0x5be0cd19137e2179;

const HASH512_K: [u64; 80] = [
    0x428a2f98d728ae22,
    0x7137449123ef65cd,
    0xb5c0fbcfec4d3b2f,
    0xe9b5dba58189dbbc,
    0x3956c25bf348b538,
    0x59f111f1b605d019,
    0x923f82a4af194f9b,
    0xab1c5ed5da6d8118,
    0xd807aa98a3030242,
    0x12835b0145706fbe,
    0x243185be4ee4b28c,
    0x550c7dc3d5ffb4e2,
    0x72be5d74f27b896f,
    0x80deb1fe3b1696b1,
    0x9bdc06a725c71235,
    0xc19bf174cf692694,
    0xe49b69c19ef14ad2,
    0xefbe4786384f25e3,
    0x0fc19dc68b8cd5b5,
    0x240ca1cc77ac9c65,
    0x2de92c6f592b0275,
    0x4a7484aa6ea6e483,
    0x5cb0a9dcbd41fbd4,
    0x76f988da831153b5,
    0x983e5152ee66dfab,
    0xa831c66d2db43210,
    0xb00327c898fb213f,
    0xbf597fc7beef0ee4,
    0xc6e00bf33da88fc2,
    0xd5a79147930aa725,
    0x06ca6351e003826f,
    0x142929670a0e6e70,
    0x27b70a8546d22ffc,
    0x2e1b21385c26c926,
    0x4d2c6dfc5ac42aed,
    0x53380d139d95b3df,
    0x650a73548baf63de,
    0x766a0abb3c77b2a8,
    0x81c2c92e47edaee6,
    0x92722c851482353b,
    0xa2bfe8a14cf10364,
    0xa81a664bbc423001,
    0xc24b8b70d0f89791,
    0xc76c51a30654be30,
    0xd192e819d6ef5218,
    0xd69906245565a910,
    0xf40e35855771202a,
    0x106aa07032bbd1b8,
    0x19a4c116b8d2d0c8,
    0x1e376c085141ab53,
    0x2748774cdf8eeb99,
    0x34b0bcb5e19b48a8,
    0x391c0cb3c5c95a63,
    0x4ed8aa4ae3418acb,
    0x5b9cca4f7763e373,
    0x682e6ff3d6b2b8a3,
    0x748f82ee5defb2fc,
    0x78a5636f43172f60,
    0x84c87814a1f0ab72,
    0x8cc702081a6439ec,
    0x90befffa23631e28,
    0xa4506cebde82bde9,
    0xbef9a3f7b2c67915,
    0xc67178f2e372532b,
    0xca273eceea26619c,
    0xd186b8c721c0c207,
    0xeada7dd6cde0eb1e,
    0xf57d4f7fee6ed178,
    0x06f067aa72176fba,
    0x0a637dc5a2c898a6,
    0x113f9804bef90dae,
    0x1b710b35131c471b,
    0x28db77f523047d84,
    0x32caab7b40c72493,
    0x3c9ebe0a15c9bebc,
    0x431d67c49c100d4c,
    0x4cc5d4becb3e42b6,
    0x597f299cfc657e2a,
    0x5fcb6fab3ad6faec,
    0x6c44198c4a475817,
];

pub struct HASH512 {
    length: [u64; 2],
    h: [u64; 8],
    w: [u64; 80],
}

impl HASH512 {
    fn s(n: u64, x: u64) -> u64 {
        return ((x) >> n) | ((x) << (64 - n));
    }
    fn r(n: u64, x: u64) -> u64 {
        return (x) >> n;
    }

    fn ch(x: u64, y: u64, z: u64) -> u64 {
        return (x & y) ^ (!(x) & z);
    }

    fn maj(x: u64, y: u64, z: u64) -> u64 {
        return (x & y) ^ (x & z) ^ (y & z);
    }

    fn sig0(x: u64) -> u64 {
        return HASH512::s(28, x) ^ HASH512::s(34, x) ^ HASH512::s(39, x);
    }

    fn sig1(x: u64) -> u64 {
        return HASH512::s(14, x) ^ HASH512::s(18, x) ^ HASH512::s(41, x);
    }

    fn theta0(x: u64) -> u64 {
        return HASH512::s(1, x) ^ HASH512::s(8, x) ^ HASH512::r(7, x);
    }

    fn theta1(x: u64) -> u64 {
        return HASH512::s(19, x) ^ HASH512::s(61, x) ^ HASH512::r(6, x);
    }

    fn transform(&mut self) {
        /* basic transformation step */
        for j in 16..80 {
            self.w[j] = HASH512::theta1(self.w[j - 2])
                .wrapping_add(self.w[j - 7])
                .wrapping_add(HASH512::theta0(self.w[j - 15]))
                .wrapping_add(self.w[j - 16]);
        }
        let mut a = self.h[0];
        let mut b = self.h[1];
        let mut c = self.h[2];
        let mut d = self.h[3];
        let mut e = self.h[4];
        let mut f = self.h[5];
        let mut g = self.h[6];
        let mut hh = self.h[7];
        for j in 0..80 {
            /* 64 times - mush it up */
            let t1 = hh
                .wrapping_add(HASH512::sig1(e))
                .wrapping_add(HASH512::ch(e, f, g))
                .wrapping_add(HASH512_K[j])
                .wrapping_add(self.w[j]);
            let t2 = HASH512::sig0(a).wrapping_add(HASH512::maj(a, b, c));
            hh = g;
            g = f;
            f = e;
            e = d.wrapping_add(t1);
            d = c;
            c = b;
            b = a;
            a = t1.wrapping_add(t2);
        }
        self.h[0] = self.h[0].wrapping_add(a);
        self.h[1] = self.h[1].wrapping_add(b);
        self.h[2] = self.h[2].wrapping_add(c);
        self.h[3] = self.h[3].wrapping_add(d);
        self.h[4] = self.h[4].wrapping_add(e);
        self.h[5] = self.h[5].wrapping_add(f);
        self.h[6] = self.h[6].wrapping_add(g);
        self.h[7] = self.h[7].wrapping_add(hh);
    }

    /* Initialise Hash function */
    pub fn init(&mut self) {
        /* initialise */
        for i in 0..64 {
            self.w[i] = 0
        }
        self.length[0] = 0;
        self.length[1] = 0;
        self.h[0] = HASH512_H0;
        self.h[1] = HASH512_H1;
        self.h[2] = HASH512_H2;
        self.h[3] = HASH512_H3;
        self.h[4] = HASH512_H4;
        self.h[5] = HASH512_H5;
        self.h[6] = HASH512_H6;
        self.h[7] = HASH512_H7;
    }

    pub fn new() -> HASH512 {
        let mut nh = HASH512 {
            length: [0; 2],
            h: [0; 8],
            w: [0; 80],
        };
        nh.init();
        return nh;
    }

    /* process a single byte */
    pub fn process(&mut self, byt: u8) {
        /* process the next message byte */
        let cnt = ((self.length[0] / 64) % 16) as usize;
        self.w[cnt] <<= 8;
        self.w[cnt] |= (byt & 0xFF) as u64;
        self.length[0] += 8;
        if self.length[0] == 0 {
            self.length[1] += 1;
            self.length[0] = 0
        }
        if (self.length[0] % 1024) == 0 {
            self.transform()
        }
    }

    /* process an array of bytes */

    pub fn process_array(&mut self, b: &[u8]) {
        for i in 0..b.len() {
            self.process(b[i])
        }
    }

    /* process a 32-bit integer */
    pub fn process_num(&mut self, n: i32) {
        self.process(((n >> 24) & 0xff) as u8);
        self.process(((n >> 16) & 0xff) as u8);
        self.process(((n >> 8) & 0xff) as u8);
        self.process((n & 0xff) as u8);
    }

    /* Generate 64-byte Hash */
    pub fn hash(&mut self) -> [u8; 64] {
        /* pad message and finish - supply digest */
        let mut digest: [u8; 64] = [0; 64];
        let len0 = self.length[0];
        let len1 = self.length[1];
        self.process(0x80);
        while (self.length[0] % 1024) != 896 {
            self.process(0)
        }
        self.w[14] = len1;
        self.w[15] = len0;
        self.transform();
        for i in 0..64 {
            /* convert to bytes */
            digest[i] = ((self.h[i / 8] >> (8 * (7 - i % 8))) & 0xff) as u8;
        }
        self.init();
        return digest;
    }
}

//8e959b75dae313da 8cf4f72814fc143f 8f7779c6eb9f7fa1 7299aeadb6889018 501d289e4900f7e4 331b99dec4b5433a c7d329eeb6dd2654 5e96e55b874be909
/*
fn main() {
    let s = String::from("abcdefghbcdefghicdefghijdefghijkefghijklfghijklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu");
    let test = s.into_bytes();
    let mut sh=HASH512::new();

    for i in 0..test.len(){
        sh.process(test[i]);
    }

    let digest=sh.hash();
    for i in 0..64 {print!("{:02x}",digest[i])}
} */
